Model comparison
GPT-5.3 Codex vs Kimi K2.7 Code
GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 43.3 on the Noometry Index. Kimi K2.7 Code costs 2.8× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.
Last verified . 5 shared benchmarks.
Summary
- They share 5 benchmarks with published results for both. GPT-5.3 Codex scores higher in 2 categories and Kimi K2.7 Code in 0 categories; 2 gaps are clear of the uncertainty.
- The widest gap is in agentic & tool use, where GPT-5.3 Codex leads 48.0 to 24.0.
- The biggest single-benchmark swing is WeirdML: 79.3% for GPT-5.3 Codex and 54.1% for Kimi K2.7 Code.
- Kimi K2.7 Code is cheaper at $0.95 / $4 per million input/output tokens, against $1.75 / $14 for GPT-5.3 Codex.
- GPT-5.3 Codex accepts more context: 400K tokens versus 262K.
- Kimi K2.7 Code has downloadable open weights; the other is API-only.
Side by side
| GPT-5.3 Codex | Kimi K2.7 Code | |
|---|---|---|
| Provider | OpenAI | Moonshot AI |
| Noometry Index | 45.8 | 43.3 |
| Released | 2026-02-05 | 2026-06-12 |
| Weights | Proprietary | Open |
| Context window | 400K | 262K |
| Max output | 128K | 262K |
| Input $ / M tokens | $1.75 | $0.95 |
| Output $ / M tokens | $14 | $4 |
| Results tracked | 8 | 19 |
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Category by category
Coding GPT-5.3 Codex leads
GPT-5.3 Codex: 48.6 (#56), Kimi K2.7 Code: 42.9 (#95)
| Benchmark | GPT-5.3 Codex | Kimi K2.7 Code |
|---|---|---|
| LMArena WebDev | 1409 | 1473 |
| WeirdML | 79.3% | 54.1% |
| ALE-Bench | 1,655 | 886.23 |
| SWE-bench Verified | 74.8% | — |
| DeepSWE | — | 30.5% |
| FrontierCode | — | 30.1% |
| SciCode | — | 47.5% |
Agentic & Tool Use GPT-5.3 Codex leads
GPT-5.3 Codex: 48.0 (#9), Kimi K2.7 Code: 24.0 (#122)
| Benchmark | GPT-5.3 Codex | Kimi K2.7 Code |
|---|---|---|
| Vending-Bench 2 | 5,940 | 5,083 |
| Terminal-Bench | 78.4% | — |
| APEX-Agents | — | 37.6% |
| GBAEval | — | 0.9% |
| METR Time Horizons | 74.5% | — |
Reasoning Not comparable
GPT-5.3 Codex: —, Kimi K2.7 Code: 39.0 (#61)
| Benchmark | GPT-5.3 Codex | Kimi K2.7 Code |
|---|---|---|
| Epoch Capabilities Index | 156.77 | 149.97 |
| SimpleBench | — | 57.9% |
| CritPt | — | 10% |
| Chess Puzzles | — | 21% |
| Surface Evolver Bench | — | 48.8% |
Math Not comparable
GPT-5.3 Codex: —, Kimi K2.7 Code: 52.9 (#48)
| Benchmark | GPT-5.3 Codex | Kimi K2.7 Code |
|---|---|---|
| FrontierMath (Tiers 1-3) | — | 54% |
| FrontierMath Tier 4 | — | 12.2% |
| OTIS Mock AIME 2024-2025 | — | 95.6% |
Knowledge Not comparable
GPT-5.3 Codex: —, Kimi K2.7 Code: 53.5 (#57)
| Benchmark | GPT-5.3 Codex | Kimi K2.7 Code |
|---|---|---|
| GPQA Diamond | — | 87.9% |
| SimpleQA Verified | — | 36.5% |
Frequently asked questions
Is GPT-5.3 Codex better than Kimi K2.7 Code?
GPT-5.3 Codex is the stronger model overall, scoring 45.8 to 43.3 on the Noometry Index. Kimi K2.7 Code costs 2.8× less per token, which makes it the better buy when GPT-5.3 Codex's lead doesn't matter for your workload.
Which is cheaper, GPT-5.3 Codex or Kimi K2.7 Code?
Kimi K2.7 Code is cheaper. It lists at $0.95 per million input tokens and $4 per million output tokens; GPT-5.3 Codex lists at $1.75 and $14.
Is GPT-5.3 Codex or Kimi K2.7 Code better for coding?
GPT-5.3 Codex scores higher on coding benchmarks: 48.6 versus 42.9 in the Noometry coding category.
Which has the bigger context window?
GPT-5.3 Codex does, with 400K tokens against 262K.
How many benchmarks do GPT-5.3 Codex and Kimi K2.7 Code share?
5 benchmarks have published results for both models. GPT-5.3 Codex has 8 scored results on Noometry and Kimi K2.7 Code has 19.